This invention relates to apparatus for handling objects by air pressure differential.
Semiconductor wafers are sliced from large crystals of semiconductor material and formed into a plurality of dice in a sequence of steps. During the processing of these wafers, they must be handled by the fabricators of the plant. One of the most convenient methods of handling wafers is by vacuum wands. These devices have a flat surface on a tip body to engage the wafer and means to apply a vacuum to an aperture in the flat surface. The tips are made of quartz, which is normally quite non-reactive and easy to fabricate. Quartz doesn't work well when the temperature of operation approaches its melting point. The tip can soften and can contaminate the wafer with silicon from the quartz. Since most wafer fabrication steps are done at high temperature, the use of quartz tips is a major problem.
Another problem inherent with quartz is that the tip must be physically thick. This limits the usefulness of the tips when a plurality of wafers are arrayed closely together. The wafers cannot be placed closer together than the tip is thick or only the end wafers can be processed.